Dynamo-electric machine control



March 7, 1939. G G LANDls ET AL 2,150,071

DYNAMO-ELECTRIC MACHINE CONTROL Filed June 21, 1934 INVENTORi ATTORNEYSPatented Mar. 7, 1939 f 2 150 071 .UNITED STATES PATENT OFFICE DYNAMO-ELECTRIC MACHINE. CONTROL George G. Landis and Norman J. Hoenie,Cleve!- land, Ohio, assignors to The Lincoln Electric Company,Cleveland, Ohio, a corporation of Ohio Application J une 21, 1934,Serial No. 731,783 Claims. (Cl. 219-8) This invention relates asindicated to control of a. portion of the circuit illustrated in Fig. 1means for dynamo-electric machines, particushowing particular variationsin the means larly welding current generators. whereby the operator mayset up the control cur- It is an object of our invention to provide arents for varying the output of the, generator. 5 control device forwelding current generators, or Referring now more particularly to thedraw- 5 more particularly welding current systems whereing and moreespecially to Fig. 1, the welding bythe operator may vary or control theoperating current generator, generally indicated at l,comcharacteristics, or more particularly, the voltprises an armature 2,series field winding 3, an ampere output characteristics of the weldingcur interpole winding 4, and an exciting winding 5-.

'10 rent generator from the welding station. The armature 2 and windings3 and 4 are con- It is a further object of our invention to pronected inseries with the welding circuit which vide a control system of thecharacter described comprises leads 6 and I which are respectivelywhereby the operator may effect the desired conconnected to a weldingelectrode 8 and the work trol over the welding current generator fromthe r 9. An are I 0 is maintained between the electrode Welding stationwithout the necessity of carrying 8 and the work. 15 any leads otherthan the usual welding leads to The exciting winding 5 is connected tosome such station. suitable source of constant potential such as an Itis a further object of our invention to provide exciter generallyindicated at I l and the exciter a control system of the characterdescribed circuit may include a series field winding l2 for which, whilethe same is responsive to certain the exciter l I. The exciter II willpreferably be 20 manipulations by the operator at the welding stadrivenby some suitable constant speed prime tion, there' is, however, nointerference with the mover, such as an electric motor, which may beusual Welding operation, nor is the setting of the the same motordriving the armature 2 of the welding current generator in any waychanged generator I. The exciting winding 5 has avariaby such changes inthe characteristics of the ble rheostat generally indicated at l3connected 25 welding circuit as occur during normal welding in seriestherewith, which. rheostat comprises a operation. resistance unit l4 anda rheostat arm l5. The

It is a further and more particular object of our arm I5 is connected toa shaft Hi to which there invention to provide acontrol system wherebythe is likewise connected a pulley or sheave ll.

volt-ampere-output characteristics of the gen- Trained about the pulleyor sheave H is a cable 30 erator may be controlled or varied in oppositeI8, the opposite ends l9 and 20 of which are se-- senses responsive tovolt-ampere characteristics cured to armatures 2| and 22 respectively.The of the welding circuit under the control of the armatures 2| and 22have respectively associated operator at the welding station, differentfrom therewith solenoid windings 23 and 24; such each other and fromsuch characteristics of the windings be nnect d together at one end 35welding circuit as occur during the normal weldand to one side of thewelding circuit, i. e., lead 6,

ing operation. by means of lead 25.

Other objects ofour invention will appear as The opposite ends of thewindings 23 and 24 are the description proceeds. respectively connectedby means of leads 26 and 40 To the accomplishment of the foregoing and21 to Contact blocks 23 and 29. The circuit related ends, saidinvention, then consists of the through either w d gs 3 01 is osed ymeans hereinafter fully described and particumeans of aswitch, gen y cae 113 from larly pointed out in the claims. lead 3| through a. switch,generally indicated at The annexed drawing and the following de- 32, andlead 33, which is connected to the opposcription set forth in detailcertain mechanism site side of the welding circuit, i. e., lead'l.embodying the invention, such disclosed means The switch, generallyindicated at 32, comprises constituting, however, but one of variousmechana contact bar 34v normally maintained in closed ical forms inwhich the principle of the invenposition under the influence of spring35. The tion may be used. contact bar 34 is moved to the opened positionIn said annexed drawing: by energization of the solenoid winding 36which Fig. 1 is a schematic diagram of an arc weldmoves the armature 31'connected to the bar 34 ing system having a control circuit arranged inupwardly. The special type of relay, generally accordance with ourinvention associated thereindicated at 38, andconnected across thewelder with; and Fig. 2 is a diagrammatic representation circuit leads 6and I by means of leads 39 and 40, 55

respectively is utilized to control the energization oi the winding 36.The relay 38 comprises a rectifler unit 4| which may conveniently be ofthe well-known copper oxide film type, a condenser 42 and a resistanceunit 43.

In connection with the operation of the relay 38, it should be notedthat in a direct current arc welding system the current flow during theoperation of the arc is not true non-pulsating, unidirectional current,but instead, due to various conditions which exist in the arc, such asperiodic bridging of the arc space by either 'a metallic vapor stream orby particles of molten metal, the volt-ampere characteristics of the arccircuit as shown by an oscillograph diagram is of a decided pulsatingnature. It is due to the pulsating nature of the welding current voltagewhich permits the flow of current through the condenser 12 and thesolenoid 36 during the normal arc welding operation. During themaintenance of the welding are, therefore, the current will flow throughthe winding 36 causing the solenoid Ell associated therewith to belifted upwardly, causing the switch 32 to be opened and the controlcircuit through the windings 23 and 24 to be deenergized. Fluctuationsor other changes in the volt-ampere characteristics of the weldingcircuit during the normal welding operation will, there fore, have noeffect on the setting of the rheostat I 3.

Connected across the welder circuit leads 6 and I by means of leads 44and 45 respectively is a solenoid winding 45 which has an armature 41associated therewith. The upper end of the armature 47, i. e., the head48, is connected by means of springs 49 and 50 to toggle link switchmembers 5i and 52 respectively. The links Eli and 52 are pivotallysupported as at 53 and M, such positions of support being arrangedrelatively to the axis of the solenoid armature ll, so that when thearmature descends due to deenergization of the winding 46, the togglelink 52 will first be moved downwardly out of contact with block 55 andinto contact with block 56 before the link 5| is moved downwardly out ofcom tact with block 28 and into contact with block 29. The parts justdescribed will pereferably be so arranged relatively to each other thatwhen the dash-pot head 51 has moved downwardly for half its possibledistance, the contact arm 52 will have been moved into engagement withthe blocklii while the arm 5| remains in contact with block 28. If,however, the head 5'! of the dash-pot is moved downwardly for the fulldistance, the arm 52 will be in contact with the block 56 and the arm 5|will be moved down-- wardly into contact with the block. 29.

fI'he operation whereby the operator at the welding station mayselectively move the,rheostat arm 15 in either direction may be brieflyexplained as follows:-Assuming that the oper ator desires to move therheostat arm IS in a clockwise direction, the operator will hold theelectrode 8 onto the work 9 without drawing the are In. Thisshort-circuit of the welding leads 6 and I will first of all result inthe flow in the welding circuit of a. true non-pulsating, unidirectionalcurrent. Due to the flow of such nonpulsating unidirectional current,the solenoid winding 36 will be deenergized due to the condenser 42being connected in series therewith so that the switch 32 will be movedto its closed position by means of the spring 35. Short-circuiting ofthe welding leads will, as previously explained. cause a deenergizationof the solenoid 46 so that the armature M may descend and move the bar52 into engagement with the contact 56. In the apparatus which has beenconstructed in accordance with. this invention, the clash-pot 5'! hasbeen so proportioned with respect to the weight of the armature 4'! thatif the operator holds the electrode ll onto the work. ii for a period often seconds, the armature ill will have descended :l'or a distancesufficient to close the arm 5t to the contact 5G and if the electrodeheld onto the work for a period of approximately twenty seconds, thearmature ll will have had an opportunity to descend for a distancesufficient so that the bar 5i is moved into engagement with the contactblock 29.

If the operator, therefore, holds the electrode onto the work, therebyshort-circuiting the weld ing circuit for a period of ten seconds, andmoves the electrode out of engagement with the work, the circuit fromlead 33 through switch 34, lead (ll, contact block 55, arm 52', arm 5i,contact block 28, lead 26, winding CZl, lead 25, will be completed,causing the winding 23 to move the armature 2i downwardly causing aclockwise rotation of the arm It for one incremerit of movement. If theoperator will then again hold the electrode onto the work for a periodof ten seconds, the circuit through the winding 23 will be againcompleted, causing the arm 15 to be moved in a clockwise direction foranother increment of movement.

If the operator should, however, hold the electrode onto the work for aperiod of twenty seconds, the armature H would settle for a distance tocause the circuit to be completed through the Winding 24 in thefollowing manner, viz:The lead 33, switch 34, lead 3|, contact blocl;56, arm 52, arm lil, contact block 29, lead 2i, winding 24, and lead 25.

While the operator holds the electrode onto the work for twenty seconds,i. e., shorts the Welding circuit for such interval, it will be notedthat the armature ll, in descending, will send an impulse of currentthrough the winding 23 before the bar 5| moves downwardly intooneasement with the contact block to, so that the rheostat arm IE willbe moved in a clockwise di' rection by one increment of movement. Forthis reason, the winding 2% and its associated armature 22 will be soproportioned that the distance of movement for each energization will betwice that of the movement of armature 21 for each energization of thewinding 23. The action of the rheostat arm it for each twenty second,short-circuited period of the welding circuit is, therefore, first, aclockwise movement to the ,right for a short increment and then acounterclockwise movement to the left for twice such short increment sothat finally the rheostat arm IE will have been moved for one shortincrement of movement in a counterclockwise direction.

Instead of short-circuiting the welding circuit by holding the electrode8 in engagement with the work 9, it may be possible to provide theelectrode holder 50 with a resistance block, generally indicated at El,which may be in the form of a carbon block extending out of the holder,and in electrical communication with the lead 5.

The operator, when he wishes to eiiect an adjustment of the rheostat I3will, therefore, turn the electrode holder 60 over and bring theresistance block 6| in engagement with the work, thus short-circuitingthe leads 6 and l, causing a flow of non-pulsating direct currentthrough such circuit to deenergize the winding 36 and also suflicientlyshort-circuiting the winding -46 so as to permit the armature 41 todescend.

The resistance of the block 6| may, of course, be different and perhapsgreater than the resistance of the electrode 8, so that when thisexpedient is employed, a somewhat different strength winding 46 may beutilized in order to secure the proper results.

In the light of the foregoing, it will be apparent that we have provideda control device for an arc welding system, whereby the operator maycontrol the setting of the rheostat on the generator which governs theoutput thereof by a mere manipulation of the electrode or associatedmeans at the welding station. Furthermore, such control system ischaracterized by the fact that the means for efiecting a setting of therheostat in no way interferes with the normal-welding operation, nor dothe usual changes in the characteristics of the welding circuit whichoccur during the normal welding operation have any effect upon thesetting of the welding current generator control rheostat.

Other modes of applying theprinciple of our invention may be employedinstead of the one explained, change being made as regards the mechanismherein disclosed, provided the means stated by any of the followingclaims or the equivalent of such stated means be employed.

We, therefore, particularly point out and distinctly claim as ourinvention:

1. A'welding system comprising a supply station including a generator, astation remote from said supply station, a conductor extending from saidsupply station to said second station, means for varying the outputcharacteristics of said generator, said last-named means including arelay at said supply station effective to thus vary the outputcharacteristics of the generator in response to flow for significantlydifferent intervals of time of control currents in said conductorsignificantly diiferent from the welding current. a

2. A welding system comprising a supply station including a weldinggenerator, a welding station remote from said supply station, aconductor extending from said supply station to said welding station,means at said supply station for varying the operating characteristicsof said generator, a control circuit for said generator regulatingmeans, a relay functionally responsive to pulsations in current flowthrough an arc in said conductor for de-energizing and energizing saidcontrol circuit and a second relay in said control circuit functionallyresponsive to current flow in said control circuit for a predeterminedlength of time to energize said generator regulating means.

3; A welding system comprising a supply station including a weldinggenerator, a welding station remote from said supply station, a weldingcircuit including a conductor extending from said supply station to saidwelding station, means at said supply station for varying thevolt-ampere characteristic of the generator in opposite sensesselectively responsive to current flow in the welding circuit fordifierent intervals of time, and a relay functionally responsive todifferent types'of current flow in the welding circuit for de-energizingand energizing said generator regulating means.

4. The combination with an electric arc welding current generator and anexternal arcing circuit, of means for varying the output of saidgenerator by adjustments significantly difierent from each other, saidmeans being selectively responsive to a short-circuiting of the arcingcircuit for different periods of time, each longer than any occurringduring the normal welding operation.

5. The combination with an electric arc welding current generator and anexternal arcing circuit,

of means for varying the output of said generator in opposite senses,said means being selectively responsive to a short-'circuiting of thearcing circuit for diflerent periods of time, each longer than anyoccurring during the normal welding operation.

GEORGE G. LANDIS. NORMAN J. HOENIE.

